The present invention relates to coating compositions based on fluorocarbon polymers. Such compositions can be used as nonstick coatings on cookware.
The cookware coating industry continues to try to improve coating compositions so that the ultimate user can have a product of superior characteristics which will last as long as possible. The same applies for nonstick coating compositions for other applications.
There are many patents relating to the use of polytetrafluoroethylene (PTFE) in cookware coating compositions. Representative of some of the more recent is U.S. Pat. No. 4,123,401--Berghmans et al. (1978).
Fluorinated vinyl ether copolymers, especially copolymerized with tetrafluoroethylene (TFE), have been available for some years. Representative patents include U.S. Pat. No. 3,132,123--Harris et al. (1964), U.S. Pat. No. 3,855,191--Doughty et al. (1974), U.S. Pat. No. 4,029,868-- Carlson (1977) directed to a terpolymer, U.S. Pat. No. 4,078,134--Kuhls et al. (1978), and U.S. Pat. No. 4,078,135--Sulzbach et al. (1978). These patents are incorporated by reference herein. The fluorinated vinyl ethers, such as in the form of copolymers, terpolymers or quadripolymers, with or without cyclic units, are generally more expensive than PTFE. Thus, they have not been considered to be a practical substitute for PTFE in nonstick coatings.